Abstract

This study aimed at identifying the statistical power tests in educational and psychological research in master's theses at Amman Arab University, as the study included all master's theses that used statistical tests (P) and (t) for the period from (2010) to (2019). The number of these studies reached (1670) dissertations, the study sample consisted of (80) dissertations, which contained (725) statistical tests, of which (313) were for (f) test, (113) for (t) test, and (218) for (r), and (100) for multiple analysis of variance and multiple regression analysis.The necessary datawerecollected to calculate the effect size and the statistical power test. The results showed that (27)% of the hypotheses contained a small effect size, and the average effect size for the (t) test reached (0.43) while the (P) test reached (0.52). The study showed that about (56.4%) of the hypotheses that were tested had a weak effect, and about (21%) of the hypotheses had a moderate statistical power test and (24.2%) of the hypotheses had a high impact.

Key words: Statistical Methods, Scientific Research, Power Test, Effect Size, Statistical Significance, Practical Significance.